Excavating for drought defences

Archeological-style digs by SCRI to measure potato varieties’ rooting capacity and potential drought resistance have unearthed some surprising results.

To see whether root length was linked to drought tolerance researcher Tim George had grown a dozen varieties under two polytunnels irrigating one plot and leaving the other to become droughted. The relative yields were then compared.

“With the rain as it is today it hardly seems appropriate to be talking about drought,” said Dr George. But with potatoes the UK’s main irrigated crop and hotter, drier summers forecast, pinpointing varieties which could use water and, by implication, nutrients more efficiently could be a valuable exercise, he explained.

Dr Tim George

Tim George’s digs are helping sort out thirsty potatoes from more water-efficient varieties

The results, as expected, showed that long-rooted Cara was drought tolerant while Maris Piper with short roots suffered when deprived of irrigation.

The work also confirmed the respective tolerance and susceptibility of two varieties, Sarpo Mira and Saturna, predicted from the European Cultivated Potato Database, noted Dr George.

“But it’s also shown that other predictions from the database are not so reliable.” Pentland Dell, with short roots, was clearly drought tolerant delivering 75% more yield when short of water, he noted.

The hope was that the genes consistently controlling rooting could eventually be identified and so used to enhance breeding programmes.

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